If you want a gaming laptop, buy a gaming laptop, which means: forget Vaio, HP, Dell, etc and buy a laptop designed for gaming.
Also forget about playing using the battery. If you have a decent hardware, it needs too much power, so gaming for more than 45 minutes is kinda hard. Besides, usually graphics cards are underclocked when using battery.
I got a MSI GT627 (Core2Quad Q9000, 4GB DDR800, 9800GTS 1024mb, 320GB 7200rm, Bluray, HDMI, 15.4" 1680x1050, etc) and quite happy with it. They main use is design (2D and 3D) but I also play sometimes. I'm used to have nice desktop computers and play with everything maxed out, and that's something I still can do with my laptop with the games I've tried: Dirt 2, Operation Flashpoint 2, Call of Duty MW2, GTA IV and many others. The score in 3DMark06 is 9700+. I personally always have the laptop on a table at home, just like if it were a desktop pc. I only use the portability when I need to take it to the school, but for the rest of the time, on a table pluged to the wall is the better way to have it. The battery is supposed to last around 2,5 hours, but don't ask me if it's true because I've barely used it.
So from my point of view, go for Asus, MSI, Sager, Deviltech, Kobalt or Cizmo, those are designed for gaming.